Safety control for a cutting machine clamping device



March 12, 1963 J. c. Do'rY ETAL SAFETY CONTROL FOR A CUTTING MACHINE CLAMPING DEVICE Filed June 17, 1959 FIG-1 United States Patent O 3,081,079 SAFETY CONTROL FOR A CUTTING MACHINE CLAMPING DEVICE Joseph C. Doty and Robert J. Buchwalder, Dayton, Ollio, assignors to Harris-Intertype Corporation, Dayton, Ohio, a corporation of Delaware Filed June 17, 1959, Ser. No. 820,944

` 2 Claims, (Cl. 269-23) This :application relates to cutting machines for cutting stacks of paper `or for cutting other sheet material, and particularly to an improved safety control for the clamp on such machines which retains the material stationary during the cutting stroke.

In guillotine type cutters, -for example of the type shown in Spiller et al. Patent 2,599,591, issued June 10, 1952, it is customary to provide a pressure operated clamping device adjacent to the cutting knife, and operable to clamp the sheet material to be cut against the top surface of the cutter table. The forces exerted by such clamps may be considerably high, capable of injuring the operator if he inadvertently places his hand-s under the clamp, or if the clamp accidentally operates while he is reaching underneath -it lto arrange material on the table. Therefore, it is desirable to provide .a safety control circuit which requires deliberate positive action by the loperator `to cause clamping movement.

Normally, the clamping operation is under control of a foot operated bar which extends approximately within a vertical plane containing the front edge of the table, and operating to swing about a hinge axis located under the table, behind the main or foot-engaging cross piece of .the bar. To assure that this bar is not accidentally engaged by the operator, while he is moving about the front of the machine as in positioning a pile ofA material to be cut, and while his hands are in the danger zone beneath the clamp, it is customary t-o provide a locking device for the clamp operating bar which must be engaged iby one hand before .the bar will be effective to operate the clamp.

The net effect of such an arrangement is to leave the operator with one hand free to maneuver the pile while his other hand operates the locking device and a foot operates the bar to produce lowering of the clamp. The Asafety feature, therefore, is attained from the requirement that only deliberate action by the operator will lower the clamp. lStrictly speaking, the operator still is able to move his free hand into the danger zone beneath the clamp, but he is warned by 1his required deliberate movements, and the clamp cannot be lowered accidentally without such deliberate procedure.

The present invention provides an improved, simplified safety control for clamp operation Awhich still requires deliberate positive action by the operator to lower the clamp, and which is safe from accidental operation, but which frees both hands of the operator for yadjustment of the pile, if desired, as the clamp descends. This improved con-trol is operated by a foot treadle, or the like, which is so located, and so hinged, that the operator must place his foot .in an unusual position, and move the foot in a manner which is somewhat abnormal lfrom a standing position.

The primary object of this invention, therefore, is to provide an improved safety control for the clamp of cutting machines, wherein lowering or clamping movement of the clamp under power is controlled by a foot operated ltreadle member which is supported well beneath the cutter table, such that .the operator must reach his foot under the table to engage the treadle, and wherein the treadle is pivotally ,mounted adjacent its edge closest to the operator such that the operator must press downwardly and forwardly with his foot, moving the ICC `machine shown in FIG. l, with the knife and clamp structure, including the clamp drive shown schematically, and with the housing o-f the machine shown in dotted outline;

|FIG. 3 is a side view on an enlarged scale, showing details of the treadle construction and its mounting; and

FIG. 4 is a plan view of the clamp control treadle.

Referring to the drawing, which shows a preferred embodiment of the present invention, a cutting machine of the type with which ,the invention is concerned is shown in dotted outline as including a cutting table 10 having -a Iforwardly projecting portion terminating in a yfront edge 12 (-FIG. l). A guillotine type cutting knife 1'5 is mounted for reciprocating movement in a generally vertical plane toward and away from the surface of tab-le 10, to cut material, for example a stack of sheets of paper, supported thereon. Immediately behind the knife y15 is a power operated clamp 1l8 which also is mounted 'for vertically reciprocating movement, under the contr-ol of draw bars 20 connected to opposite sides thereof. Each ofthe draw bars is fastened at its lower end through a hinge joint 22 to a connecting rod 23 which in turn is pivotally secured to one end of a bell crank 25 mounted to pivot in a generally vertical plane therebeneath. The two bell cranks are joined by a tie rod 28 for movement in unison, and Ithe power to move the clamp 18 is provided by -a double-acting hydraulic motor 30 of the piston-cylinder type which has its piston rod 32 extended and pivotaltly connected to one of the bell cranks 25, as shown in FIG. 2.

Control of the motor 30 may be provided by any suitable hydraulic control system, for example of the type described and illustrated in the aforementioned Patent 2,599,591. Thus, the directional control valve 33 lfor the motor 30 will govern raising and lowering of clamp 18, and movement of this valve 'is in turn controlled by an operating cable 35 which is fastened at one end to a yoke piece'l.

The control of cable movement is provided by a foot operated treadle indicated by the ygener-al reference numeral 40, and including mounting :brackets 42 which are bolted to the base 43 of the machine, 'and to which are secured the stationary plates 44 of conventional spring hinges 45. These hinges are of the Well-known type which incorporate therein torsion springs acting to bias the relatively mofvable plates of the hinge in a desired direction.

In the particular arrangement shown herein the movyable hinge plate 47 is bolted to the treadle plate 50 and the torsion springs are arranged to urge the treadle plate into a normally raised position, ie. biased in a counterclockwise direction las viewed in FIG. 3. Stop tabs 52 extend from .the Iforward ends of mounting brackets 42 and engage the under surface of the forward edge of treadle plate 50 to limit the movement of the treadle plate under the spring hinge bias. An arm 55 is bolted to lthe normally upper or lowermost end of treadle plate y50 and is pivotally connected to the cable yoke -37 through -a hinge pin I57.

With reference .to FIGS. l and 3, it will be noted that the hinge axis about which the treadle plate 50 swings is located at 60, the center line of the hinges 45, and this axis is substantially at 'the forward or lowermost edge of the treadfle plate, although spaced somewhat rearwardly. of the entremetforward edge of plate 50. Thus in the normal or atrestpositionthe "treadle plate is 'rbiased kto extend in la plane projectingupwardly and rearwardly with reference to the front of the cutting machine, andthe operator must place'his'foot upon the treadle plate and press downward and-inward,`with -refereuce to the base'of the machine,- to actuate the clamp control valve 33.

` Furthermore, the extreme .forward'edge of treadle plate 50, and therefore 'i-tshinge axis, is located' beneath and rearwardly of thevfront of table 10, within, with referxence to the lmachine base, an area boundedfby a Vertical plane'extending through the forward edge-of table 10, as indicated by the dot dashlinez in FIG. 1. VThe operator stat-ion is normally infront of'table Y10, 'outside of the `area bounded by this plane, where the spaced apart operating levers'65 for controlling theknifes cutting cycle are mounted. Thus :the operator, standing in .front of the plane 62, must deliberately'place his foot within-the area'underneath the table to engage vthe treadle plate 50 and operate the clamp. During'nor-mal 'movement about the front of the machine the operator will not normally place his foot within this area, and 'even if this should happen accidentally,- hewould `engage the eX- treme forward-end of'treadle 50 and would tend to 'move that plate in a direction `the same' as the bias of spring hinges 45, or against the stopsSZ. Thus, even if vhe should accidentally engage the treadie plate no `movement of the clamp willoccur since the treadle 1will not be depressed ina direction tomovevl the operating cable 3S.

While the -form of apparatus herein 'described constitutes apreferred `embodiment of the invention, 'it `is .to be understood that this .invention isnot vlimited toY this precise form of apparatus andthat vchanges may lbe made therein without departing from the scope of the invention which is defined in lthe appended claims.

What is claimed is:

1. A safety control construction forca machine having -a horizontal work tablemOUnted on a base, .a .power driven clamp member arranged to clamp material in prer`determined position "on 'the top of said table, and selectively operable drive means'for said clamp memlber; said safety construction comprising means on said table forming a work station at one edgetof said table top in fixed relation to Asaid clamp member, a foot operated treadle supponted from said base below said table top and substantially inwardly beneath said table Itop from a verti- 'cal plane through one said edge of said table top at said work station, pivot means connected to said treadle adjacent the edge .thereof closest to said vertical plane, biasing means cooperating with said pivot means supporting said treadle in a normal position with the surface thereof extending-in an inclined plane directed upwardly `and rearwardly with respect to said work station, said Awork station being in such spaced relation to said pivot `means that an operatori is required .to stand at said work station to control said machine'and in such standing position is required to extend one'foot in a deliberate and abnormal manner beyond said station and underneath lsaid `table Atop to place such one foot in operative position on said treadle, 4and means connecting said treadle to said'selectively operable drive k'means yfor vproducing a lowering movement of said clamp member in response -to pivotal motion of said treadle against said Ibiasing `means 'from its said normally inclined lposition 'down `and away `from said Work station toward a horizontal position and continued holding of said treadle away yfrom its said normally inclinedv position.

2. In-a'machine 'as defined in :claim 1, stop meanS mounted adjacent said treadle and located outwardly of said pivot means toward said work station and said vertical 'pl-a`.ne, said stop means engaging'the lowermost edge of said treadle forwardly of said pivot "means,

'References Cited in the tile-of this patent UNITED STATES PATENTS v2,305,735 Reichant Dec. 22, 1942 2,321,380 Hacklander June 8, 1943 2,599,591 Spiller June 10, 1952 FOREIGN PATENTS 409,798 France Apr. 30, 1910 

1. A SAFETY CONTROL CONSTRUCTION FOR A MACHINE HAVING A HORIZONTAL WORK TABLE MOUNTED ON A BASE, A POWER DRIVEN CLAMP MEMBER ARRANGED TO CLAMP MATERIAL IN PREDETERMINED POSITION ON THE TOP OF SAID TABLE, AND SELECTIVELY OPERABLE DRIVE MEANS FOR SAID CLAMP MEMBER; SAID SAFETY CONSTRUCTION COMPRISING MEANS ON SAID TABLE FORMING A WORK STATION AT ONE EDGE OF SAID TABLE TOP IN FIXED RELATION TO SAID CLAMP MEMBER, A FOOT OPERATED TREADLE SUPPORTED FROM SAID BASE BELOW SAID TABLE TOP AND SUBSTANTIALLY INWARDLY BENEATH SAID TABLE TOP FROM A VERTICAL PLANE THROUGH ONE SAID EDGE OF SAID TABLE TOP AT SAID WORK STATION, PIVOT MEANS CONNECTED TO SAID TREADLE ADJACENT THE EDGE THEREOF CLOSEST TO SAID VERTICAL PLANE, BIASING MEANS COOPERATING WITH SAID PIVOT MEANS SUPPORTING SAID TREADLE IN A NORMAL POSITION WITH THE SURFACE THEREOF EXTENDING IN AN INCLINED PLANE DIRECTED UPWARDLY AND REARWARDLY WITH RESPECT TO SAID WORK STATION, SAID 